support running java-interop tests

Author: olhotak

test/dotc/tests.scala

@@ -120,5 +120,12 @@ class tests extends CompilerTest {
       "-Xprompt",
       "#runs", "2"))
 
+  val javaDir = "./tests/disabled/java-interop/"
+  @Test def java_all = compileFiles(javaDir+"pos/")
+
+  @Test def java_2409 = compileDir(javaDir+"failing/t2409")
+  @Test def java_1751 = compileDir(javaDir+"failing/t1751")
+  @Test def java_294 = compileDir(javaDir+"failing/t294")
+
   //@Test def dotc_compilercommand = compileFile(dotcDir + "tools/dotc/config/", "CompilerCommand")
 }

test/test/CompilerTest.scala

@@ -24,13 +24,13 @@ class CompilerTest extends DottyTest {
     compileDir(Directory(path), args, xerrors)
 
   def compileDir(dir: Directory, args: List[String], xerrors: Int)(implicit defaultOptions: List[String]): Unit = {
-    val fileNames = dir.files.toArray.map(_.toString).filter(_ endsWith ".scala")
+    val fileNames = dir.files.toArray.map(_.toString).filter(name => (name endsWith ".scala") || (name endsWith ".java"))
     compileArgs(fileNames ++ args, xerrors)
   }
 
   def compileFiles(path: String, args: List[String] = Nil)(implicit defaultOptions: List[String]): Unit = {
     val dir = Directory(path)
-    val fileNames = dir.files.toArray.map(_.toString).filter(_ endsWith ".scala")
+    val fileNames = dir.files.toArray.map(_.toString).filter(name => (name endsWith ".scala") || (name endsWith ".java"))
     for (name <- fileNames) {
       println(s"testing $name")
       compileArgs((name :: args).toArray, 0)

tests/disabled/java-interop/pos/t1751/A1_2.scala renamed to tests/disabled/java-interop/failing/t1751/A1_2.scala

@@ -1,6 +1,6 @@
 @ImplementedBy(classOf[Provider])
 trait Service {
-  def someMethod()
+  def someMethod(): Unit
 }
 
 class Provider